Currently, you're not actually passing in a list, but a tuple:
https://docs.python.org/2/tutorial/datastructures.html#tuples-and-sequences

myList = [0, 1, 2, 3]
myTuples = (0, 1, 2, 3)

Lists are generally an ordered collection of the same type of objects. Tuples are generally an ordered collection of heterogeneous objects.